[GRASSLIST:1975] Re: r.support & i.composite & number of colors

[Roger S. Miller]

Gail Higginbottom wrote:
 
> Dear Grass users,
> 
> Sometime ago it was confirmed to me that I could use r.patch to join many
> small maps together to make one big map. I have a number of
> UK Ordnance Survey tiles that I have imported into Grass. I wish to join
> them to have a map of the entire region of western Scotland.  I have used
> the command
>  r.patch input=nm20.ras,nm22.ras,nm24.ras output=test.patch
> 
> but regardless of what I input the output "map" is always blank and white.
> 
> What have I missed? Can anybody assist me here?

You haven't described your process in a lot of detail, so I'll take a
shot in the dark...

Make sure that you set your region before running r.patch.  According to
the manual page for r.patch, the region must be set to the region
covered by the final, patched map.  You can use g.region to set your
region.


Roger Miller
Lee Wilson and Associates